One known robot control apparatus, which is disclosed in Japanese Patent Application Publication No. 2010-269419, grasps an object to be positioned using a robot arm. A user manipulates a controller to control motion of the robot arm to thereby locate the object to a predetermined target position in a three-dimensional space, at which the object is desired to be located. Three coordinate axes, which are labelled x, y, and z, define the three-dimensional space. The user also manipulates the controller to control motion of the robot arm to thereby direct the object toward a predetermined target orientation to which the object should be oriented in the three-dimensional space.
The controller of the disclosed robot control apparatus is provided with a first push-button switch provided for the x, y, and z axes and a second push-button switch provided for the x, y, and z axes. Pushing on the first push-button switch by a user causes the controller to limit movement of the object in all the x, y, and z axes of the three-dimensional coordinate system. Similarly, pushing on the second push-button switch by a user causes the controller to limit rotation of the object around each of the x, y, and z axes of the three-dimensional coordinate system. This limitation of rotation restricts change of the direction of the object. The limitation of both movement and change of direction of the object aims to prevent unintentional movement and unintentional change of direction of the object due to, for example, the shakes of the user's hands manipulating the controller.